Free Tool · Health
Free BMI Calculator
Find your Body Mass Index in seconds. Enter your height and weight below — the result updates instantly, with a visual guide to where you fall on the healthy range.
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Reference & method
BMI with the health context behind the number
BMI = weight in kilograms ÷ height in metres squared (kg/m²). The calculator converts imperial inputs before applying the same formula.
Calculation flow
Source & scope
World Health Organization (WHO) — adult BMI definition and reference ranges.
Official reference: View source
Assumptions & limits
- BMI is a screening measure, not a diagnosis.
- The adult categories do not apply to children and teenagers in the same way.
- Body composition, muscle mass and other health factors are not captured by BMI alone.
Why this tool is different
The page explains the formula and its limitations so the user gets context, not a health conclusion from one number.
Common questions
BMI Calculator FAQ
What is a healthy BMI range?
For most adults, a BMI between 18.5 and 24.9 is considered a healthy range. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese.
Is BMI accurate for everyone?
BMI is a general screening tool based on height and weight only. It does not account for muscle mass, bone density, age, or body composition, so athletes and older adults may get results that don't reflect their actual health.
How is BMI calculated?
BMI is calculated as weight in kilograms divided by height in meters squared (kg/m²). For imperial units, it is weight in pounds divided by height in inches squared, multiplied by 703.
Can I use this BMI calculator for children?
No. This calculator is designed for adults. Children and teenagers need age- and gender-specific BMI percentile charts, which work differently from the adult categories used here.